JPH07218863A - Projection exposure device - Google Patents

Abstract

PURPOSE:To improve the compatibility of a projection optical system consisting of plural projection optical units by arranging a lattice pattern of brightness in each of positions corresponding to the object face and the image face of the projection optical system and observing moire stripes for each projection optical unit which are generated at the time of throwing the illuminating light. CONSTITUTION:An operation means 204 of this projection exposure device moves a carriage 170 and a detection unit 145 in the X direction and the Y direction respectively so that the detection unit 145 is placed in the visual field of a projection optical unit A. The operation means 204 detects the pitch or moire stripes formed on lattice patterns 16 and the direction or the angle of rotation between lattices by the detection unit 145 while driving an actuator 207 to rotate a prism. Next, the pitch of moire stripes and the angle of rotation are detected with respect to a projection optical unit B, and such adjustment is performed by a difference computing element 206 that pitches of moire stripes and angles of rotation of projection optical units A and B match each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection exposure apparatus, and more particularly to self-correction of a projection optical system including a plurality of projection optical units.

[0002]

2. Description of the Related Art In recent years, liquid crystal display panels have been widely used as display elements for word processors, personal computers, televisions and the like. A liquid crystal display panel is manufactured by patterning a transparent thin film electrode on a glass substrate into a desired shape by a photolithography technique. As a device for this lithography, a mirror projection type aligner has been used, which exposes an original image pattern formed on a mask onto a photoresist layer on a glass substrate through a projection optical system.

By the way, in the conventional mirror projection type aligner, in order to enlarge the exposure area,
The exposure area was divided and exposed. Specifically, the exposure area on the plate which is the substrate to be exposed is divided into, for example, four areas, and the first mask and the first area are subjected to scanning exposure,
The circuit pattern of the first mask is transferred to the first region.
Next, the first mask and the second mask are exchanged, and the plate is moved stepwise so that the exposure region of the projection optical system and the second region overlap. Then, the second mask and the second region are scanned and exposed to transfer the circuit pattern of the second mask onto the second region. Hereinafter, similar steps are repeated for the third mask, the fourth mask, the third region and the fourth region, and the circuit patterns of the third mask and the fourth mask are respectively set to the third pattern.
Was transcribed to the 4th area and the 4th area.

As described above, when the exposure area is divided and exposed, the throughput (amount of exposed substrate per unit time) is low because scanning exposure is performed a plurality of times for one exposure area. Further, in the case of divided exposure, a seam is generated between the adjacent exposure areas, and therefore the seam accuracy needs to be improved. Therefore, it is necessary to bring the magnification error of the projection optical system close to 0, and it is required to significantly improve the alignment accuracy, which leads to a high cost of the apparatus.

On the other hand, it is conceivable to increase the size of the projection optical system in order to collectively scan and expose one large exposure area without performing divided exposure. However, in order to increase the size of the projection optical system, it is necessary to manufacture a large-sized optical element with extremely high precision, resulting in an increase in manufacturing cost and an increase in size of the apparatus. In addition, an increase in the size of the projection optical system causes an increase in aberration, that is, a reduction in image forming performance.

Therefore, a projection exposure apparatus has been proposed in which the projection optical system is composed of a plurality of projection optical units that form an erect image of equal magnification (Japanese Patent Application No. 5-161588). In the projection exposure apparatus proposed in this application, each projection optical unit is composed of a first partial optical system and a second partial optical system, and each partial optical system is a reflective optical system such as a Dyson type or Offner type. As described above, in the projection exposure apparatus in which the projection optical system is composed of a plurality of projection optical units, there is an advantage that one large exposure area can be scanned and exposed as a whole even if each projection optical unit is small.

[0007]

However, in the above-described projection exposure apparatus, since each projection optical unit includes a plurality of reflecting surfaces, the projection optical units may be routed through each projection optical unit due to an error in mounting the reflecting surface or the like. An error occurs in the orientation of the formed images. Since the projection optical system is composed of a plurality of projection optical units, the images formed through the respective projection optical units during scanning exposure are corrected unless the above-mentioned error in the mutual orientation of the images is corrected. There was the inconvenience that the consistency between the two was lost.

The present invention has been made in view of the above-mentioned problems, and provides a projection exposure apparatus having a high matching between the images of the projection optical units while forming the projection optical system with a plurality of projection optical units. The purpose is to do.

[0009]

In order to achieve the above object, the projection exposure apparatus according to the present invention has the following configuration.
For example, as shown in FIG. 3, the projection exposure apparatus of the present invention is formed on the first substrate by moving the first substrate and the second substrate relative to the projection optical system (21A to 21C). The exposed pattern is projected onto the second substrate through the projection optical system, and the projection optical system comprises:
A plurality of projection optical units (2) for forming an equal-magnification erect image of the pattern formed on the first substrate on the second substrate.
1A, 21B, 21C), and each of the plurality of projection optical units includes a first deflecting member for deflecting light from the first substrate, and a reflecting member for reflecting light from the first deflecting member. A mirror and a second deflecting member for deflecting light from the reflecting mirror toward the second substrate, and at least an image side is a telecentric optical system, and the optical system is provided through the plurality of projection optical units. It is configured to include a correction unit for correcting an error in the orientation of the plurality of images formed on the second substrate.

According to a preferred aspect of the present invention, the correcting means has a first bright / dark grating (1) having a predetermined pitch and positioned at a position corresponding to the object plane of the projection optical system.
5), a second bright / dark grating (16) having the same pitch as the first bright / dark grating and positioned at a position corresponding to the image plane of the projection optical system, and the second bright / dark grating by the projection optical unit. Observing means (13, 1) for observing the image of the first bright and dark lattice and the moire fringes generated from the second bright and dark lattice.
4) and positioning correction means for correcting the positioning of each of the plurality of projection optical units based on the moire fringes observed by the observation means.

[0011]

As described above, according to the present invention, in a scanning type projection exposure apparatus having a projection optical system including a plurality of projection optical units, bright and dark gratings are respectively provided at positions corresponding to the object plane and the image plane of the projection optical system. Place the pattern. Each lattice pattern is a pattern in which transparent portions and opaque portions are alternately arranged in parallel at equal intervals, and are arranged substantially parallel to each other and in substantially the same direction. Then, the illumination light that has passed through the two bright and dark lattice patterns and the projection optical system is received, and the moire fringes are observed for each projection optical unit.

As will be described later, if the images formed through the projection optical units have the same orientation, the moire fringes observed in the projection optical units have the same pitch. In other words, it is possible to measure the pitch of the moire fringes for the two projection optical units and detect the error in the mutual orientation of the images formed via the projection optical units. Therefore, by making the directions of the reflecting surfaces (first and second deflecting members, reflecting mirrors) of the respective projection optical units substantially constant so that the moire fringes have the same pitch,
The direction of the image formed via each projection optical unit can be made substantially constant. As a result, highly consistent projection exposure between the projection optical units is possible.

[0013]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a perspective view showing the configuration of a projection exposure apparatus according to an embodiment of the present invention. 2 is a diagram showing the configuration of the projection optical system of the projection exposure apparatus of FIG. In Figure 1,
The direction in which the mask 108 on which a predetermined circuit pattern is formed and the plate 109 made of a resist-coated glass substrate is conveyed (scanning direction) is the X axis, and the mask 108 is
The direction orthogonal to the X axis in the plane of the
The normal direction of 8 is the Z axis.

The illustrated projection exposure apparatus has an illumination optical system 110 for uniformly illuminating the mask 108 in the XY plane in the figure.
Is equipped with. Below the mask 108 (-Z direction),
A projection optical system including a plurality of projection optical units 102a to 102g is arranged. Each projection optical unit has the same configuration. Below the projection optical system, a plate 109 is mounted on a stage 160 so as to be substantially parallel to the XY plane. During the scanning exposure, the mask 108 and the plate 109 are integrally moved in the arrow direction (X0 direction) in the figure.

FIG. 2 is a diagram schematically showing the configuration of each projection optical unit. The illustrated projection optical unit includes a first partial optical system (121 to 124), a field stop 125,
It is composed of the second partial optical system (126 to 129). The first partial optical system (121 to 124) and the second partial optical system (126 to 129) are Dyson type optical systems and have the same configuration.

The first partial optical system is a prism 130 that deflects the light from the mask 108 in the + X axis direction (right side in the figure).
A first reflecting surface 121, a plano-convex lens 122 for converging the light reflected by the first reflecting surface 121, and a concave mirror 123 for reflecting the light passing through the plano-convex lens 122 to the plano-convex lens 122, The second reflecting surface 124 of the prism 130 deflects the light incident through the plano-convex lens 122 in the −Z direction in the figure. As described above, the first partial optical system and the second partial optical system have exactly the same configuration. In FIG. 2, the constituent elements of the second partial optical system are denoted by reference numerals different from those of the constituent elements of the first partial optical system, but redundant description of the configuration of the second partial optical system is omitted.

Illumination light transmitted through the mask 108 is + X direction (right side in the figure) on the first reflecting surface 121 of the prism 130.
And is incident on the plano-convex lens 122. The light converged by the plano-convex lens 122 is reflected by the concave mirror 123 in the −X direction (on the left side in the figure), and then enters the plano-convex lens 122 again. The light that has passed through the plano-convex lens 122 is reflected by the prism 130.
Is deflected in the −Z direction (downward in the figure) by the second reflecting surface 124 of the second reflective surface 124, and a primary image of the pattern of the mask 108 is formed between the first partial optical system and the second partial optical system. In this way, the primary image formed by the first partial optical system (121 to 124) is a unity-magnification image of the mask 108 having a lateral magnification in the X direction of +1 and a lateral magnification in the Y direction of -1. . A field stop 125 is arranged at the position where the primary image is formed.

The light from the primary image that has passed through the field stop 125 is deflected in the + X direction (right side in the figure) by the first reflecting surface 126 of the prism 131 of the second partial optical system, and enters the plano-convex lens 127. . The light converged by the plano-convex lens 127 is reflected by the concave mirror 128 in the −X direction (left side in the figure),
The light enters the plano-convex lens 127 again. The light passing through the plano-convex lens 127 is deflected in the −Z direction (downward in the figure) by the second reflecting surface 129 of the prism 131, and a secondary image of the pattern of the mask 108 is formed on the plate 109.

As described above, the first partial optical system and the second partial optical system
The partial optical system of the second partial optical system has exactly the same configuration, and the second partial optical system forms a unity-magnification image of a primary image having a lateral magnification in the X direction of +1 and a lateral magnification in the Y direction of -1. Therefore, the secondary image formed on the plate 109 via the first and second partial optical systems is the same-erected image of the mask 108 (an image in which the lateral magnification in both the X and Y directions is +1). Become. here,
The projection optical unit including the first and second Dyson type partial optical systems is a telecentric optical system on both sides (both the object side and the image side).

Generally, in the Dyson type optical system, the maximum visual field region defined as a region in which the aberration is sufficiently small has a semicircular shape. Therefore, the opening formed in the field stop 125 is defined within the semi-circular maximum field area. In this embodiment, the field stop 125 has a trapezoidal opening. In FIG. 1, the trapezoidal visual field region 108 on the mask 108 is provided by the visual field diaphragms respectively arranged in the projection optical units 102a to 102g.
a to 108 g are specified. These visual fields 108
The images a to 108g are transmitted through the projection optical system to the plate 1
In the exposure regions 109a to 109g on 09, an erect image of equal size is formed.

Here, the projection optical units 102a to 102a
02d is arranged so that the corresponding visual field regions 108a to 108d are linearly arranged along the Y direction in the drawing, that is, the scanning orthogonal direction. On the other hand, the projection optical unit 102e
To 102g are arranged so that the corresponding visual field regions 8e to 8g are arranged in a straight line different from the visual field regions 8a to 8d along the Y direction.

Incidentally, the projection optical units 102a to 102
2d longitudinal direction and projection optical unit 102e to 1
The longitudinal direction of 02g is parallel to the X-axis, and the reflecting surfaces of the projection optical units 102a to 102d are close to the reflecting surfaces of the projection optical units 102e to 102g, that is, the first group of projection optical units 102a to 1g.
02d and the second group of projection optical units 102e to 102
It is configured to face g. Furthermore, the projection optical units 102a, 102e, 102 are arranged along the Y direction.
The first group and the second group are alternately arranged in the order of b, 102f, 102c, 102g, and 102d.

The visual field region 108a on the mask 108
To 108g are defined by the shape of the aperture of the field stop in the corresponding projection optical unit. Therefore, the illumination optical system 110 includes the visual field regions 108a to 108a.
It is not necessary to provide an optical system for strictly defining 8 g. As described above, the exposure regions 109a to 109d are linearly formed on the plate 109 along the Y direction via the projection optical units 108a to 108d, and the exposure regions 10 are formed via the projection optical units 108e to 108g.
9e to 109g are linearly formed along the Y direction. These exposure areas 109a to 109g are equal-magnification erect images of the visual field areas 108a to 108g on the mask 108.

Next, the projection optical units 102a to 102a
Fields of view 108a through 108 defined by 02g
The positional relationship of g on the mask 108 will be described. The short side portions of the trapezoidal visual field regions 108a to 108d and the short side portions of the trapezoidal visual field regions 108e to 108g are arranged so as to face each other, and the triangular end portion of each visual field region and the visual field adjacent thereto. The corresponding triangular ends of the regions overlap in the X direction (scanning direction).

As described above, the reason why the first-group visual field regions 108a to 108d and the second-group visual field regions 108e to 108g are alternately arranged in the Y direction is that each projection optical unit is a double-sided telecentric optical system. , The areas occupied by the projection optical units 102a to 102g on the XY plane become larger than the corresponding visual field areas 108a to 108g.

That is, in the visual field regions 108a to 108d defined by the visual field diaphragms of the projection optical units 102a to 102d arranged linearly, Y is provided between the respective regions.
A gap occurs in the direction. As a result, the projection optical unit 1
With only 02a to 102d, it becomes impossible to secure a continuous exposure area on the plate 109 in the Y direction. Therefore, the projection optical units 102e to 1
02g is attached to the corresponding visual field regions 108e to 108e.
8 g complements the Y-direction intervals of the visual field regions 108a to 108d to secure a continuous exposure region in the Y direction. Note that in the present embodiment, the visual field regions 108a to 108a.
Field of view 1 located at the end in the Y direction most in g
The end portions of 08a and 108d coincide with the end portion in the Y direction of the region where the pattern of the mask 108 is formed.

Thus, the visual field region 1 on the mask 108
In 08a to 108g, the total length of the visual field regions along the scanning direction (X direction) is constant at any position in the scanning orthogonal direction (Y direction). That is, the exposure regions 109a to 109g, which are erect images of the same size as the visual field region
Also in the above, the total sum of the lengths of the visual field regions along the scanning direction (X direction) is constant at any position in the scanning orthogonal direction (Y direction). As a result, by scanning exposure, the plate 1
It is possible to obtain a uniform exposure light amount distribution over the entire surface on 09.

FIG. 3 is a view showing the arrangement of the correction means of the projection exposure apparatus according to the embodiment of the present invention. In the figure, the projection optical units 21A to 21C are Dyson type optical systems having the configuration shown in FIG. The illustrated correction means includes a bright and dark grid pattern 15 arranged at a position corresponding to the projection pattern surface of the projection optical system.

A bright and dark grid pattern 16 having the same structure as the grid pattern 15 is provided at a position corresponding to the image plane of the projection optical system. The grid patterns 15 and 16 are patterns having the same pitch (patterns in which transparent portions and opaque portions are alternately arranged in parallel at equal intervals) and are positioned substantially parallel to each other and in substantially the same direction. Figure 3
In FIG. 1, only a part of the grid patterns 15 and 16 are shown for the sake of clarity.

The correction means shown in the figure further includes a light-receiving lens 13 disposed below the projection optical system in the figure, and an image sensor 14 disposed further below the light-receiving lens 13 in the figure.
It has and. In addition, at least the object side (projection optical units 21A to 21C side) of the light receiving sensor 13 is configured to be telecentric. Further, as indicated by the broken line in the figure, the light receiving sensor 13 and the image sensor 14 are integrally configured so as to be movable in the direction along the image plane of each projection optical unit. You can move downwards. Furthermore, the grating pattern 16 and the light receiving surface of the image sensor 14 are in a conjugate relationship. Thus, the illumination light 1 from the illumination optical system (not shown) passes through the grating pattern 15, each projection optical unit and the grating pattern 16, and is received by the image sensor 14 via the light receiving lens 13. .

Next, the structures of the grating patterns 15 and 16, the light receiving lens 13 and the image sensor 14 of this embodiment will be described with reference to FIGS. FIG. 4 is a perspective view schematically showing the structure of the stage in this embodiment, and adopts a coordinate system corresponding to FIG. Further, FIG. 5 is an XZ sectional view of this embodiment. In FIG. 4, the mask 108
Is a mask stage 150 movable along the XY plane.
It is mounted on top by a vacuum adsorption technique. As shown in FIG. 5, the mask stage 150 has an opening for passing the exposure light passing through the mask 108. The pattern surface (the surface on which the pattern is provided) of the mask 108 placed on the mask stage 150 is the lower side (the plate 109 side).

Returning to FIG. 4, the plate 109 is mounted on the plate stage 160 movable along the XY plane by a vacuum suction method. Here, the mask stage 150 and the plate stage 160 are each set to Y
Carriage 17 having a "C-shaped" cross section in the Z plane
It is set to 0. The carriage 170 is provided so as to be movable along the X direction.

Mask stage 15 on carriage 170
At a portion different from 0 (an end portion on the carriage 170 adjacent to the mask stage 150), a glass support 143 for supporting the substrate glass 141 having the lattice pattern 15 is fixedly provided. As shown in FIG. 5, this glass support base 14
3 also has an opening for passing the light from the illumination optical system 110 that passes through the grating pattern 15. The lattice pattern 15 of the substrate glass 141 placed on the glass support 143 is on the lower side (plate 109 side) and is located in the same plane as the pattern surface of the mask 108 on the mask stage 150.

Returning to FIG. 4, the glass support base 1 for supporting the substrate glass 142 having the lattice pattern 16 on a portion of the carriage 170 different from the plate stage 150.
44 is fixed. As shown in FIG. 5, the glass support table 144 has an opening for passing the light passing through the grating pattern 16. The glass support 144
The grid pattern 16 of the substrate glass 142 placed on top
Are located in the same plane as the upper surface (mask 108 side) of the plate 109.

Returning to FIG. 4, on the glass substrate 141
The upper grid pattern 15 and the grid pattern 16 on the glass substrate 142 have a pitch along the X direction in the drawing. The carriage 170 is provided with a guide 146 which is a groove extending in the Y direction in the drawing. Here, the detection unit 145 having the light receiving lens 13 and the image sensor 14 shown in FIG. 3 is movably attached to the groove of the guide 146. Therefore, the detection unit 145 can move along the Y direction in the drawing. Although not shown, the detection unit 145 is provided with a linear encoder so that the position of the detection unit 145 in the Y direction can be detected.

As shown in FIG. 5, the grating pattern 16 on the glass substrate 142 and the image pickup surface of the image sensor 14 are conjugated by the light receiving lens 13 of the detection unit 145. The lattice pattern 16 on the glass substrate 142 and the lattice pattern 15 on the glass substrate 141 are
Since the projection optical system (122 to 128) arranged between the grid patterns 15 and 16 has a conjugate relationship, the image sensor 14 has the grid pattern 1
An image of No. 5 (third-order image) and an image of the lattice pattern 16 (correctly, the first-order image) are formed. That is, the image sensor 1
Moire fringes of the grid pattern 15 and the grid pattern 16 are formed on the surface 4.

Although the grid pattern 15 is provided on the carriage 170 in this embodiment, the mask 108 is used.
It may be provided on a part of the mask stage 150 that supports the. In addition, the grid pattern 16 is a carriage 17
However, it may be provided on a part of the stage 160 that supports the plate 109.

Here, when the light receiving lens 13 is not object-side telecentric (the projection optical systems 122 to 128 side is telecentric), the magnification on the image sensor 14 is changed due to the distance variation between the light receiving lens 13 and the grating pattern 16. It is not preferable because it changes and it becomes difficult to accurately detect the pitch. In this embodiment, since the light receiving lens 13 is telecentric on the object side, when the light receiving lens 13 and the image sensor 14 move integrally,
Even if the distance from the grid pattern varies, the pitch can be accurately detected.

FIG. 6 is a diagram for explaining the relationship between the positional deviation of the reflecting surface of the projection optical unit and the direction of the image formed, and FIG. 6A shows only the reflecting surface of the second partial optical system. In the case of displacement, (b) shows the case where the entire second partial optical system is displaced. The projection optical unit shown in FIG. 6 is a Dyson type optical system having the configuration shown in FIG.

In FIG. 6A, when the prism having the first and second reflecting surfaces of the second partial optical system is rotated about the optical axis 2 by the angle θ in the illustrated direction, the position of the field stop 7 is changed. The orientation of the primary image 32 of the projection pattern 31 formed on the optical axis is not affected at all, but the secondary image 33 of the projection pattern 31 formed at the image plane position of the projection optical unit is at an angle 2θ about the optical axis 2. It will rotate in the direction shown.

On the other hand, in FIG. 6B, when the entire second partial optical system rotates about the optical axis 2 in the direction shown by the angle θ, the primary pattern of the projection pattern 31 formed at the position of the field stop 7. The orientation of the image 32 is not affected at all, but the projection pattern 3 formed at the image plane position of the projection optical unit
The secondary image 33 of No. 1 is rotated about the optical axis 2 by the angle 2θ in the illustrated direction. In other words, the direction of the image formed can be adjusted by rotating the reflecting surface of the projection optical unit around the optical axis 2. in this way,
If there is a rotation error in the mounting of the reflecting surface of each projection optical system,
Since the orientations of the images formed via the respective projection optical units are not constant, the matching between the images formed via the respective projection optical units is impaired during scanning exposure. Further, even if the entire projection optical unit is attached to the entire other projection optical unit with a rotation error, the matching between the images formed is impaired.

On the other hand, since the grid pattern 15 and the grid pattern 16 are located at positions corresponding to the projection pattern plane and the image plane of the projection optical system, respectively, the two grid patterns are in a conjugate relationship with each other. The grid pattern 15 and the grid pattern 16 are arranged substantially parallel to each other and in substantially the same direction. Therefore, the moire fringes can be observed in the image sensor 14. The pitch p of the moiré fringes observed is defined as the pitch of the bright and dark gratings and the rotation angle between the gratings (the secondary image of the grating pattern 15 and the grating pattern 16
(Corresponding to the crossing angle with) is represented by the following equation (1). p = d / δ (1)

Since the pitch d of the bright and dark grating is a constant, it is detected that the crossing angle δ between the secondary image of the grating pattern 15 and the grating pattern 16 is constant if the pitch p of the observed moire fringes is constant. can do. Here, only the absolute value of the intersection angle δ of the two grid patterns corresponds to the pitch p of the moire fringes, and there are two possible directions of the secondary image of the grid pattern 15 with respect to the grid pattern 16. Therefore, while measuring the pitch of the moire fringes for each projection optical unit and appropriately rotating the reflecting surface of each projection optical unit around the optical axis, the pitch of the moire fringes is made substantially constant between the projection optical units. If the direction of the reflecting surface is also adjusted, it is possible to correct the error in the direction between the images formed via the projection optical units.

Specifically, according to FIG. 6A, when only the reflecting surface of the prism of the second partial optical system of the projection optical unit is rotated for correction, the prism and the plano-convex lens are separated. There is a need. On the other hand, according to FIG. 6B, when the second partial optical system of the projection optical unit and the reflecting surface thereof are both rotated and corrected, the entire optical system indicated by reference numeral 20 in FIG. It is necessary to rotate in the direction of.

Next, the adjusting mechanism of the projection optical unit in this embodiment will be described with reference to FIG. Figure 7
7A is an XY plan view of the projection optical unit, and FIG.
7B is an XZ plan view of the projection optical unit, and FIG.
(C) is a YZ plan view of the projection optical unit. In addition,
The projection optical unit shown in FIG. 7 includes a second partial optical system (1
26-129) only.

In FIGS. 7A and 7B, the reflecting surface 12
The prism 131 having 6,129 is held by the support frame 209a, and the lens barrel 210 that integrally supports the plano-convex lens 127 and the concave mirror 128 is held by the support frame 209b. Here, the support frames 209a and 209b are integrated through hinge portions 209c provided at three locations along the XZ plane including the optical axis Ax of the plano-convex lens 127 and the concave mirror 128 shown by the dashed line in the figure. ing. Prism 13
1 and the lens barrel 210 are configured to be swingable in the YZ plane with the hinge portion 209c as the center of rotation. In addition,
At this time, the hinge portion 209c, which is the center of rotation, is located so as not to block the light flux passing through the projection optical system.

A brief description will be given with reference to FIG. 7C, which is a plan view of FIG. 7B viewed from the -X direction side in the drawing. Figure 7
In (c), the support frame 209a has two openings 209a ₁ and 209a ₂ in the YZ plane. The prism 131 is attached so as to cover these openings 209a ₁ and 209a ₂ . In FIG. 7C, the hinge portion 209c, which is the center of rotation, is shown by being shaded in the figure. As shown in the figure, the hinge portion 209c is formed in the opening 2
It can be seen that the connecting portions are provided along the Z direction so as to sandwich 09a ₁ and 209a ₂ and are outside the field of view defined by the field stop 125 in FIG.

Returning to FIG. 7A, the supporting frames 209a, 2
Elastic hinge 2 comprising 09b and hinge portion 209c
An actuator 207 including a piezoelectric element or a laminated piezoelectric element and a displacement sensor 208 including an electrostatic capacitance type sensor are provided at 09.

As shown in FIG. 8, when the actuator 207 is expanded or contracted, the reflecting surface of the prism 131 rotates about the hinge portion 209c with respect to the lens barrel 210, and the image by the projection optical unit shows the rotation amount of the prism 131. It rotates by twice the rotation amount of θ. Here, the displacement sensor 2
When the displacement amount of the support frames 209a and 209b at the position of 08 is Δ and the distance between the hinge portion 209c and the displacement sensor 208 in the Y direction is L, the rotation amount θ of the prism 131.
Is represented by θ≈Δ / L (2). Here, when the displacement sensor 208 has an accuracy of about 10 nm and the distance L in the Y direction between the hinge portion 209c which is the rotation center and the displacement sensor 208 is 100 mm, 10 nm / 100 mm = 0.1 μrad (0.02 ″) (3) The rotation amount θ of the prism can be measured with the accuracy of (3) Therefore, if a piezo element having a resolution of 1 nm is used as the actuator 207, the rotation amount of the prism can be controlled with the accuracy of 0.1 μrad. You can

In the example shown in FIGS. 7 and 8, the lens barrel 210 holding the plano-convex lens 127 and the concave mirror 128 is used.
While the prism 131 is rotationally controlled, the prism 131, the plano-convex lens 127, and the concave mirror 128 are integrally held by the lens barrel, and the actuator 207 is provided at the connecting portion between the lens barrel and the exposure apparatus main body. If the displacement sensor 208 and the elastic hinge 209 are provided, the second
It becomes possible to control the rotation of the entire partial optical system.

Further, in the example shown in FIGS. 7 and 8, the hinge portion 209c is provided at three places in the YZ plane including the optical axis, but the distance between the prism 131 and the plano-convex lens 127 cannot be sufficiently secured. In this case, this hinge part 20
9c may be provided at the end of the elastic hinge 209 in the −Y direction. At this time, the hinge portion 209c becomes one member having a shape extending in the Z direction and does not include the optical axis XZ.
It is provided in a plane.

Next, the control system of the actuator 207 and the displacement sensor 209 will be described with reference to FIG. In FIG. 9, the light-receiving lens 13 has a magnifying power and forms a magnified image of moire fringes formed on the lattice pattern 16 on the imaging surface of the image sensor 14. The calculation means 204 is
The pitch of the moire fringes is measured based on the output from the image sensor 14. Further, the calculation means 204 stores the pitch of the moire fringes in the memory 205. The difference calculator 206 takes the difference between the pitch of the moire fringes and the pitch of the moire fringes stored in the memory, and drives the actuator 207 so that this difference becomes a constant amount.

A specific example of the above control will be described in detail with reference to FIGS. 3 to 5, 9 and 10. Note that FIG.
FIG. 6 is a flowchart showing an example of the adjusting operation according to the present embodiment.

[Step 0] In step 0, the calculation means 204 moves the carriage 170 in the X direction so that the detection unit 145 is positioned within the field of view of the projection optical unit 21A, and moves the detection unit 145 in the Y direction. Let Then, the calculating means 204 shifts to the next step 1.

[Step 1] In step 1, the calculating means 204 drives the actuator 207 to rotate the prism, and at the same time, the pitch p of the moire fringes formed on the lattice pattern 16 by the detection unit 145 and the mutual lattice. The direction of the rotation angle δ is detected. After that, the calculation means 204 moves to the next step 2.

[Step 2] In step 2, the detection result of step 1 is stored in the memory 205, and the process proceeds to the next step 3.

[Step 3] In step 3, the calculating means 204 determines whether or not the adjustment has been completed for all the projection optical units. In this description, the adjustment relating to the projection optical units 21B and 21C has not been completed, and therefore the process proceeds to step 4.

[Step 4] In Step 4, the calculating means 204 performs Step 0 with respect to the projection optical unit 21B.
And step 1 are executed, and the process proceeds to step 5.

[Step 5] In step 5, the difference calculator 206 determines whether the pitch p and the direction of the rotation angle δ of the projection optical unit 21B are equal to those of the projection optical unit 21A stored in the memory 205. To judge. If they are not equal, the calculation means 204
Moves to the next step 6, and if they are equal, moves to step 11.

[Step 6] In step 6, the calculation means 204 drives the actuator 207 so that the output of the difference calculator 206 becomes constant. At this time, the displacement sensor 208 monitors the rotation angle and rotation direction of the prism. Then, the calculation means moves to step 7.

[Step 7] In step 7, the calculation means 204 determines whether or not the adjustment has been completed for all the projection optical units. In this description, the adjustment relating to the projection optical unit 21C has not been completed, so the process proceeds to step 8.

[Step 8] In step 8, the calculating means 204 performs step 0 for the projection optical unit 21C.
And step 1 are executed, and the process proceeds to step 9.

[Step 9] In step 9, the difference calculator 206 determines whether the pitch p and the direction of the rotation angle δ of the projection optical unit 21B are the same as those of the projection optical unit 21A stored in the memory 205. To judge. If they are not equal, the calculation means 204
Moves to the next step 10, and if they are equal, moves to step 11.

[Step 10] In step 10, the calculation means 204 drives the actuator 207 so that the output of the difference calculator 206 becomes constant. At this time, the displacement sensor 208 monitors the rotation angle and rotation direction of the prism. Then, the calculation means moves to step 11.

[Step 11] In step 11, the calculating means 204 makes all the projection optical units 21A to 21C.
Regarding whether or not the adjustment has been completed. In step 11, all projection optical units 21
Since the adjustment has been completed for A to 21C, the description is ended.

In the above description, three sets of projection optical units 21A to 21C are described as an example, but as shown in FIG. 3, the adjusting operation is performed even when there are three or more sets of projection optical units. Is the same. further,
In the above description, the projection optical unit 21A is used as the reference, but the projection optical unit used as the reference may be any projection optical unit. Further, in the above description, the detection unit 145 is configured to be movable only in the Y direction (scanning orthogonal direction), but the detection unit 145 is movable in the XY plane as shown in FIG. May be provided.

In an actual projection exposure apparatus, the projection optical system is composed of many projection optical units. Therefore, it is preferable that the pair of grating patterns 15 and 16 occupy the entire area of the projection optical system. However, the grating patterns occupying the areas of at least two adjacent projection optical units are respectively formed on the projection pattern surface and the image. The correction operation may be performed over the entire projection optical system while sequentially moving in the plane. Further, since there is an error in the grid pitch in the actual grid pattern, it is preferable to refer to the average pitch in the entire observation visual field when measuring the pitch of the moire fringes.

As described above, in the present embodiment, the error in the orientation of the image between the projection optical units due to the assembly error of the projection optical units and the like is measured, and the image between the projection optical units is measured based on the result. By finely adjusting the error of the orientation of, the pattern images through the projection optical units can be transferred onto the plate with high consistency. Further, by regularly performing the fine adjustment, stable scanning exposure can be performed at all times. In the present embodiment, the present invention has been described by taking the projection optical unit including two Dyson type partial optical systems as an example. However, the projection optical unit is an Offner type 2 optical system.
It may be composed of one partial optical system, or may be composed of one or two partial optical systems of other reflection type.

Although the light receiving lens 13 and the image sensor 14 as the observing means are movable in the above-described embodiments, the plurality of light receiving sensors and the image sensor are arranged below each projection optical unit (each projection optical unit). Image side) may be arranged respectively. In this case, it is desirable to provide each of the light receiving lenses so that the optical axes of the plurality of light receiving lenses coincide with the optical axes of the projection optical units.

[0070]

As described above, according to the present invention, while forming a projection optical system with a plurality of projection optical units, it is possible to perform scanning projection exposure with high matching between the images of the projection optical units.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a projection exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a projection optical system of the projection exposure apparatus of FIG.

FIG. 3 is a diagram showing a configuration of a correction unit of the projection exposure apparatus according to the embodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a stage according to an example of the present invention.

FIG. 5 is a sectional view of a projection exposure apparatus according to an embodiment of the present invention.

FIG. 6 is a diagram for explaining the relationship between the positional deviation of the reflecting surface of the projection optical unit and the direction of the image formed, in which (a) is the case where only the reflecting surface of the second partial optical system is displaced. To
(B) shows a case where the entire second partial optical system is displaced.

FIG. 7 is a diagram showing a configuration of a projection optical unit,
(A) is an XY sectional view, (b) is an XZ sectional view, and (c) is Y.
It is a Z top view.

FIG. 8 is a diagram schematically showing an adjusting operation of the projection optical unit.

FIG. 9 is a block diagram of a projection exposure apparatus according to an embodiment of the present invention.

FIG. 10 is a flowchart showing an example of the operation of the projection exposure apparatus according to the embodiment of the present invention.

[Explanation of symbols]

 15 and 16 bright and dark grating 13 imaging lens 14 image sensor 102 projection optical unit 108 mask 109 plate 110 illumination optical system 125 field stop

Claims (8)

[Claims] 1. A first substrate and a second substrate are moved relative to a projection optical system so that a pattern formed on the first substrate is transferred to the second substrate via the projection optical system. In a projection exposure apparatus that performs projection exposure on a substrate, the projection optical system includes a plurality of projection optical units that form an equal-magnification erect image of a pattern formed on the first substrate on the second substrate, Each of the plurality of projection optical units includes a first deflecting member that deflects the light from the first substrate, a reflecting mirror that reflects the light from the first deflecting member, and a light from the reflecting mirror. Is a telecentric optical system at least on the image side, and is formed on the second substrate via the plurality of projection optical units. Compensates for orientation errors between multiple images A projection exposure apparatus, characterized in that it is provided with a correcting means for correcting it. 2. The correction means has a first bright-dark grating having a predetermined pitch and positioned at a position corresponding to the object plane of the projection optical system, and the same pitch as the first bright-dark grating. And a second bright / dark grating positioned at a position corresponding to the image plane of the projection optical system, an image of the first bright / dark grating by the projection optical unit, and moire fringes generated from the second bright / dark grating are observed. 2. An observing unit for observing the moiré fringes, and a positioning correcting unit for correcting the positioning of each of the plurality of projection optical units based on the Moire fringes observed by the observing unit. The projection exposure apparatus described. 3. The projection optical unit reimages a first partial optical system that forms an intermediate image of a pattern formed on the first substrate, and the intermediate image on the second substrate. And a second partial optical system, wherein each of the first and second partial optical systems includes the first and second deflecting members and the reflecting mirror, respectively. 2. The projection exposure apparatus according to item 2. 4. The projection exposure apparatus according to claim 2, wherein the positioning correction unit corrects the orientations of the first and second deflecting members of each of the plurality of projection optical units. . 5. The positioning correction means corrects the orientations of the first and second deflecting members and the reflecting mirror of each of the plurality of projection optical units, according to claim 2 or 3. The projection exposure apparatus described. 6. The first bright-dark grating and the second bright-dark grating occupy regions of at least two adjacent projection optical units, and are movable in the pattern plane and the image plane, respectively. The projection exposure apparatus according to any one of claims 2 to 5. 7. The projection exposure apparatus according to claim 2, wherein the first bright-dark grating and the second bright-dark grating occupy the entire area of the projection optical system. . 8. The light-receiving optical system, wherein the observing means forms an image of the moire fringes by illumination light that passes through the first bright-dark grating, the plurality of projection optical units, and the second bright-dark grating. 8. The projection according to claim 2, further comprising a light receiving unit that photoelectrically converts the image of the moire fringes, and the light receiving optical system is telecentric on at least the projection optical unit side. Exposure equipment.